In the United States, the modern Thanksgiving holiday tradition is commo
nly traced to a 1621 celebration at Plymouth in present-day Massachusetts.
The 1621 Plymouth feast and thanksgiving was prompted by a good harvest. A
s President of the United States, George Washington proclaimed the first na
tion-wide thanksgiving celebration in America marking November 26, 1789, "a
s a day of public thanksgiving and prayer to be observed by acknowledging w
ith grateful hearts the many and signal favours of Almighty God"Thank
sgiving in the United States was observed on various dates throughout histo
ry. From the time of the Founding Fathers until the time of Lincoln, the da
te Thanksgiving was observed varied from state to state. The final Thursday
in November had become the customary date in most U.S. states by the begin
ning of the 19th century. Thanksgiving was first celebrated on the same dat
e by all states in 1863 by a presidential proclamation of Abraham Lincoln.
Influenced by the campaigning of author Sarah Josepha Hale, who wrote lette
rs to politicians for around 40 years trying to make it an official holiday
, Lincoln proclaimed the date to be the final Thursday in November in an at
tempt to foster a sense of American unity between the Northern and Southern
states.[23] Because of the ongoing Civil War and the Confederate States of
America's refusal to recognize Lincoln's authority, the concept of "nation
wide" Thanksgiving did not totally take effect until Reconstruction was com
pleted in the 1870s.It was not until December 26, 1941, that the unif
ied date changed to the fourth Thursday (and not always final) in November—
this time by federal legislation. President Franklin D. Roosevelt, after tw
o years earlier offering his own proclamation to move the date earlier, wit
h the reason of giving the country an economic boost, agreed to sign a bill
into law with Congress, making Thanksgiving a national holiday on the four
th Thursday in November.